Phonograph sound box



Sept. 7 1926. 1,599,148

B. R; sEABRooK PHoNoGRAPi SOUND Box A -Fled April 18. 1922 wzza;

Patented Sept. 7, 1926.Y

y UNITEDl STATES isAGrsriiJa RoADs sEABRoox, or MISHAWAKA, INDIANA.

rHoNoGRArii soUND Box.

'y Application led April 18, 1922. Serial No. 555,076.

My invention relatesr to improvements in phonograph sound boxes and it more especially Vconsists of the features hereinafter pointed out in the annexed claims.

The purpose of my inventioncis to provide-a sound'. boxthat .shall morecorrec-tly translate the mechanical vibrations of aV record into acoustic' vibrations than is pos sible with sound boxes constructed in thev ordinal" manner' thatA has a s eciall shaped lining of a plastic self-hardeningV composition which is non-absorbent and nonresponsive to the sound waves produced by the diaphragm; that also provides a special arrangement of diaphragm gaskets in order to insure a greater freedom and truthfulness of the diaphragm vibrations; and that also provides a specially shaped formed diaphragm- With these and other ends in View, I i1- lustrate in the accompanying drawing such instances of adaptation as will dis-close the broad underlying' features without limiting myself to the specific details shown thereon or described herein.

Fig. 1 is a side elevation of the sound box.

Fig. 2 is a front elevation of Fig. 1.

Fig. 3 is a side elevation in section ofv Fig.

1. Fig. 4 is an enlarged elevation of the diaphragm gaskets and bearing rings.

Fig. 5 is an enlarged elevation of modi-v fied bearing rings.

I may use sound box casing 1 provided with a flange 5 and secured to a tone arm terminal 3 by means of a iiange 2. This teriminal has an opening 4 which leads into the interior of the sound box. The flange 2 may be insulated from the sound box as shown. A retaining ring 11 is secured to the front of the sound box by means of screws 12 and it serves to hold the diaphragm in place.

Thefinterior surface of the sound box is scored or roughened atl() in order to assist in holding the composition 6 in engagement therewith- This composition is formed with an ogee curve 7, 8. The curve starts from the opening 4 and progresses into the rounded thickness 7 of convex form and theny passesinto the concave shape reducing the thickness of the composition 6 to its thinnest part at 8, and this concave portion terminates into a uniform thickness at 9 which thickness is vsomewhat less than that of the convex portion 7. A metallic coni-r cally shaped bearing ring 16 may be imbedded in the composition 6 near its exterior as especially shown in Fig. 4. The ring 16 is placed in the composition while it is plastic and by reason of its conical shape is held therein. It is assembled in any suitable manner'to'insure the apex 17 being concen` tric with the flange 5 of thel sound box, and also parallel with the front face of this flange. If desired, the ring 16 may be formed as shown at in Fig. 5, wherein it has an annular iianged projection 36. The

iiange 36 serves to hold the apex 17 con- K' centric with the sound'box within practicalk limits.

The retaining'ring 11 shown in enlarged rrelation in Fig. 4 has a shoulder 14 formed on its inner face. This shoulder coacts with the inside of flange 5 and serves to hold the ring 11 concentric with the sound box casing. It is provided with an integral conical retaining -ring 13 having its apex 15 di rectly opposite the apex 17 of the ring 16. In Fig. 3 the retaining ring is shown as 39 with an annular groove 40 between the cons ical portion 13 and the shoulder 14, while in Fig. 5 a retaining ring 33 is shown with a shoulder 37 against .which ar removable metallic conically shaped bearing ring 34 abuts- The diaphragm is held between two flat rubber gaskets 1S having its exterior edge 19 removed from the inner face of the flange 5. This allows the diaphragm to vibrate freely in the direction of the exaggerated diagonal lines 39 shown in Fig. 5

with its nodal point between the apex 15 i and the apex 17 and in line with these. The diaphragm is formed curving as shown in Fig. 3 with a very sharp short radius curve at 21 between the curved center and the straight rim 20 which is held between the gaskets 18. It is reinforced at its center by means of an. interior washer 23 and the large diameter exterior washer 22.- These washers are very thin approximately the same in thickness as the diaphragm itself. The special features-of the diaphragm as to its composition, etc., is not claimed herein but is made thesubject of separate prosecution.

, The usual stylus bar 25 is secured to the diaphragm at 24 at one end and at theother end is attached to the enlarged portion 26 which serves as a needle carrier. Italso has a pivotal axis 27 that is held by conical ended screws 29 between the ears `28. tl1at project fronrthe sound box lange 25. The needle 32 is held in the opening 3l in the nsual'manner by thumb screw 3,0.

Then the composition 6 is given other shapes than that shown, the rresults are markedly different. In some cases producing squeaky and in other casessharpemetallic-like tones which detract from the purity ot' thesound waves comprised inthe `record` that isheing played. The diaphragm may be made with more than one of the short radius Acurves 2l. In any event7 such curves arefonnd opposite .the convex shape 8 of the composition. It is impossibleto state from thestandpoint of the physicist just ,what actuallytalres place between the diaphragm and the curved face of. the composition 6, but as to the resultsithere is no vsuperiority applicant claims a composition lining tota sound box having a reverse curve iaCeadJacent the diaphragm 1n its broadest yaspect,l 1s well as the solid metallic bearingiings in relation to the elastic gasliets.

lll/That I claim is:

Insound boxes, a suitable flanged casing, anda composition lining therein having an opening,therethrough,the lining beingI disposed in varyingA thicknesses greatest around the openingiaridithinnest between the opening' and,tlieiiperiphery thereof and of intermediate thickness at the outer edge.

:In testimony whereof I aftix my signa` ture.

BGSTER ROADS SEABRGOK. 

